Neurofibromatosis Type I

  • Etiology: hamartomatous disorder involving ectoderm and mesoderm
  • Imaging:
    — Orbit: bilateral optic nerve gliomas
    — Skull: macrocephaly, dysplasia of greater wing of sphenoid
    — Brain: brainstem glioma, focal areas of signal intensity (FASI) – T2 hyperintense foci in cerebellar peduncle, brainstem, thalamus, globus pallidus and subcortical white matter
    — Spine: dural ectasia, enlarged neuroforamina, kyphoscoliosis from neurofibromas, pseudoarthrosis
    — Bones: pseudoarthrosis, anterior bowing of long bones, inferior rib notching (ribbon ribs), tibial dysplasia, non-ossifying fibromas around knees
    — GI: polyps (myenteric plexiform neurofibromas), GIST tumors
    — GU: pheochromocytoma
    — Vascular: Moya Moya syndrome, aneurysms, mid aortic syndrome, renal artery stenosis
    — Throughout body: plexiform neurofibromas, macrodystrophia lipomatosa
  • Complications: 5-10% of neurofibromas degenerate into malignant peripheral nerve sheath tumors
  • Clinical: for diagnosis of neurofibromatosis-1 you need at least 2 of the following
    >6 cafe au lait spots
    >2 pigmented iris hamartomas
    axillary or inguinal freckling
    optic nerve gliomas
    first degree relative with neurofibromatosis-1
    dysplasia of greater wing of sphenoid

Cases of Neurofibromatosis Type I

CXR and MRI of neurofibromatosis type I
CXR shows a posterior mediastinal mass. Coronal and sagittal T1 MRI without contrast of the thoracic spine shows dural ectasia.